OBJECTIVE: The black rhinoceros (Diceros bicornis) is an endangered mammal for which a captive breeding program is part of the conservation effort. Black rhinos in zoo\'s often suffer from chronic infections and heamochromatosis. Furthermore, breeding is hampered by low male fertility. To aid a research project studying these topics, we sequenced and assembled the genome of a captive male black rhino using ONT sequencing data only.
METHODS: This work produced over 100 Gb whole genome sequencing reads from whole blood. These were assembled into a 2.47 Gb draft genome consisting of 834 contigs with an N50 of 29.53 Mb. The genome annotation was lifted over from an available genome annotation for black rhino, which resulted in the retrieval of over 99% of gene features. This new genome assembly will be a valuable resource in for conservation genetic research in this species.

The study of endobiotic ciliates from the intestines of various zoo mammals is important for revealing the influence of various factors on endobiont communities. In this paper we describe the species diversity of endobiotic ciliates from the faeces of the eastern black rhinoceros Diceros bicornis michaeli (male and two females, mother and daughter) kept in the zoo. Seven species of the ciliates were found, among them Rhinozeta rhinozeta, R. triciliata and Prototapirella clypeata were observed in the rhinos only. The other two, Monoposthium sp. and Triplumaria sp., according to their morphology should have been identified as new ciliate species. Successful transmission of the endobionts from parents to the young rhino in the zoo was demonstrated. R. rhinozeta was investigated with the using of the methods of the light and immunofluorescence microscopy and molecular phylogeny. The composition and phylogeny of the family Cycloposthiidae were discussed.

In contrast to understanding spinescence in savanna woody species, little is known about the functions of plant secondary metabolites (PSM). Negative effects of PSMs on individual animal performance potentially translate into negative effects on herbivore population growth. Hence, understanding PSM functions is important for the conservation of savanna megafauna. We tested the view that black rhinoceros (Diceros bicornis) diet preference is not affected by spinescence or total phenolic abundance. We hypothesized that the composition of phenolic mixtures, however, would affect preference. Furthermore, we tested our data from 71 woody species for a trade-off between structural and chemical defenses. Spinescence type, and spinescence generally, did not deter black rhino feeding. Using eco-metabolomic data, we found that total abundance of phenolics did not affect preference, but mixture composition did and that the probability of spinescence trading off against phenolics depended on the mixture. We note that our study was restricted to black rhino and that diet preferences of other mammal herbivores might be influenced by subtle differences in phenolic mixtures. However, our results did support a previous, more detailed study of phenolic profiles of six species showing the same patterns in relation to preference generalised across mammal herbivore species in savannas. Our results represent substantial advancement in the understanding of the roles of PSMs, especially flavonoid compounds, in the functioning of savanna ecosystems, and highlight the need to dig deeper into broad groups of traits such as spinescence or total phenolics to improve understanding of woody plant defenses in savannas.

Proactive approaches that anticipate the long-term effects of current and future conservation threats could increase the effectiveness and efficiency of biodiversity conservation. However, such approaches can be obstructed by a lack of knowledge of habitat requirements for wildlife. To aggregate and assess the suitability of current information available on habitat requirements needed for proactive conservation, we conducted a systematic review of the literature on elephant and rhinoceros habitat requirements and synthesized data by combining a vote counting assessment with bibliometric and term maps. We contextualized these numeric and terminological results with a narrative review. We mapped current methods, results, terminology, and collaborations of 693 studies. Quantitative evidence for factors that influence the suitability of an area for elephants and rhinoceros was biased toward African savanna elephants and ecological variables. Less than one third of holistic approaches considered equal amounts of ecological and anthropogenic variables in their assessments. There was a general lack of quantitative evidence for direct proxies of anthropogenic variables that were expected to play an important role based on qualitative evidence and policy documents. However, there was evidence for a segregation in conceptual frameworks among countries and species and between science versus policy literature. There was also evidence of unused potential for collaborations among southern hemisphere researchers. Our results indicated that the success of proactive conservation interventions can be increased if ecological and anthropogenic dimensions are integrated into holistic habitat assessments and holistic carrying capacities and quantitative evidence for anthropogenic variables is improved. To avoid wasting limited resources, it is necessary to form inclusive collaborations within and across networks of researchers studying different species across regional and continental borders and in the science-policy realm.
Colaboración de Fuerzas hacia la Conservación Proactiva de Elefantes y Rinocerontes Resumen Los enfoques proactivos que anticipan los efectos a largo plazo de las amenazas a la conservación actuales y futuras podrían incrementar la efectividad y la eficiencia de la conservación de la biodiversidad. Sin embargo, dichos enfoques pueden ser frenados por una falta de conocimiento de los requerimientos de hábitat para la vida silvestre. Para sumar y evaluar la idoneidad de la información disponible sobre los requerimientos del hábitat necesitados para la conservación proactiva realizamos una revisión sistemática de la literatura sobre los requerimientos de hábitat de los elefantes y rinocerontes y sintetizamos los datos combinándolos en una evaluación de conteo de votos con mapas bibliométricos y de términos. Contextualizamos estos resultados numéricos y terminológicos con una revisión narrativa. Mapeamos los métodos, resultados, terminologías y colaboraciones actuales de 693 estudios. La evidencia cuantitativa de los factores que influyen sobre la idoneidad de un área para los elefantes y los rinocerontes estuvo sesgada hacia los elefantes de la sabana africana y las variables ecológicas. Menos de un tercio de las estrategias holísticas consideró cantidades iguales de variables ecológicas y antropogénicas en sus evaluaciones. Hubo una carencia generalizada de evidencias cuantitativas para los indicadores directos de las variables antropogénicas que se esperaba tendrían un papel importante con base en la evidencia cualitativa y los documentos de las políticas. Sin embargo, hubo evidencias de una segregación en el marco conceptual entre los países y las especies y entre la ciencia versus la literatura política. También hubo evidencias de un potencial sin explotar para las colaboraciones entre los investigadores del hemisferio sur. Nuestros resultados indicaron que el éxito de las intervenciones de conservación proactiva puede incrementarse si las dimensiones ecológicas y antropogénicas se integran a las evaluaciones holísticas del hábitat y si se mejoran las capacidades de carga holísticas y las evidencias cuantitativas de las variables antropogénicas. Para evitar gastar los recursos limitados, es necesario formar colaboraciones inclusivas dentro y a lo largo de las redes de investigadores que están estudiando a diferentes especies en las fronteras regionales y continentales y dentro del ámbito de la ciencia política.

BACKGROUND: Understanding rhino movement behavior, especially their recursive movements, holds significant promise for enhancing rhino conservation efforts, and protecting their habitats and the biodiversity they support. Here we investigate the daily, biweekly, and seasonal recursion behavior of rhinos, to aid conservation applications and increase our foundational knowledge about these important ecosystem engineers.
METHODS: Using relocation data from 59 rhinos across northern Namibia and 8 years of sampling efforts, we investigated patterns in 24-h displacement at dawn, dusk, midday, and midnight to examine movement behaviors at an intermediate scale and across daily behavioral modes of foraging and resting. To understand recursion patterns across animals\' short and long-term ranges, we built T-LoCoH time use grids to estimate recursive movement by each individual. Comparing these grids to contemporaneous MODIS imagery, we investigated productivity\'s influence on short-term space use and recursion. Finally, we investigated patterns of recursion within a year\'s home range, measuring the time to return to the most intensively used patches.
RESULTS: Twenty four-hour displacements at dawn were frequently smaller than 24-h displacements at dusk or at midday and midnight resting periods. Recursion analyses demonstrated that short-term recursion was most common in areas of median rather than maximum NDVI values. Investigated across a full year, recursion analysis showed rhinos most frequently returned to areas within 8-21 days, though visits were also seen separated by months likely suggesting seasonality in range use.
CONCLUSIONS: Our results indicate that rhinos may frequently stay within the same area of their home ranges for days at a time, and possibly return to the same general area days in a row especially during morning foraging bouts. Recursion across larger time scales is also evident, and likely a contributing mechanism for maintaining open landscapes and browsing lawns of the savanna.

\'Eliska,\' an endangered black rhino (Diceros bicornis), died suddenly in Mkomazi National Park in Tanzania in 2016. Three Amblyomma gemma ticks were collected from Eliska\'s body, and four ticks were collected from the surrounding field. We conducted 16S rRNA targeted high-throughput sequencing to evaluate the overall composition of bacteria in the ticks\' microbiomes and investigate whether the ticks could be the cause of Eliska\'s death. The ticks collected from Eliska\'s body and the field were found to differ in their bacterial composition. Bacillus chungangensis and B. pumilus were the most commonly found bacteria in the ticks collected from the field, and B. cereus and Lysinibacillus sphaericus were the most commonly found in the ticks collected from Eliska\'s body. The abundance was higher in the ticks collected from the field. In contrast, the equity was higher in the ticks collected from Eliska\'s body. No known pathogenic bacteria that could explain Eliska\'s sudden death were found in any of the ticks. The differences between the microbiome of ticks collected from Eliska\'s body and from the field indicate that the microbiome of ticks\' changes through the consumption of blood.

Success of animal translocations depends on improving postrelease demographic rates toward establishment and subsequent growth of released populations. Short-term metrics for evaluating translocation success and its drivers, like postrelease survival and fecundity, are unlikely to represent longer-term outcomes. We used information theory to investigate 25 years of data on black rhinoceros (Diceros bicornis) translocations. We used the offspring recruitment rate (ORR) of translocated females-a metric integrating survival, fecundity, and offspring recruitment at sexual maturity-to detect determinants of success. Our unambiguously best model (AICω = 0.986) predicted that ORR increases with female age at release as a function of lower postrelease adult rhinoceros sex ratio (males:females). Delay of first postrelease reproduction and failure of some females to recruit any calves to sexual maturity most influenced the pattern of ORRs, and the leading causes of recruitment failure were postrelease female death (23% of all females) and failure to calve (24% of surviving females). We recommend translocating older females (≥6 years old) because they do not exhibit the reproductive delay and low ORRs of juveniles (<4 years old) or the higher rates of recruitment failure of juveniles and young adults (4-5.9 years old). Where translocation of juveniles is necessary, they should be released into female-biased populations, where they have higher ORRs. Our study offers the unique advantage of a long-term analysis across a large number of replicate populations-a science-by-management experiment as a proxy for a manipulative experiment, and a rare opportunity, particularly for a large, critically endangered taxon such as the black rhinoceros. Our findings differ from previous recommendations, reinforce the importance of long-term data sets and comprehensive metrics of translocation success, and suggest attention be shifted from ecological to social constraints on population growth and species recovery, particularly when translocating species with polygynous breeding systems.

Although Salmonella spp. infection has been identified in captive and free-ranging rhinoceros, clinical cases in black rhinoceros ( Diceros bicornis ) calves have not been described. This case series describes clinical salmonellosis in four black rhinoceros calves. Two calves developed self-limiting diarrhea, recovering after treatment. The other two cases were fatal. One of the fatal cases had a short clinical course, whereas the other case was protracted, with signs reflecting multiple organ system involvement. In all cases, diagnosis was by fecal culture and/or quantitative polymerase chain reaction. A variable clinical presentation, which is typical for salmonellosis in domestic hoofstock, was a feature of these rhinoceros cases. Similarly, postmortem pathology in black rhinoceros calves was consistent with domestic neonatal ungulates with salmonellosis. Potential predisposing factors for infection were considered to be primiparity of the dam and failure of passive transfer in the calf. The case investigation included attempts to identify the source of infection, which was aided by organism serotyping. In one case, the patient\'s dam and another conspecific in the facility were shown to be asymptomatic shedders of the organism strain responsible for disease in the calf. Further surveillance of captive rhinoceros Salmonella spp. carrier status is needed to inform screening recommendations for this taxa.

In 2016, an emaciated black rhinoceros (Diceros bicornis) was found in Kruger National Park, South Africa. An interferon-γ response was detected against mycobacterial antigens, and lung tissue was positive for Mycobacterium bovis. This case highlights the risk that tuberculosis presents to rhinoceros in M. bovis-endemic areas.

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